How many glasses of milk would you like?
解析：
how many +可数名词 表示数量的多少
how much +不可数名词 表示数量的多少
例如,一杯牛奶 a glass of milk 属于可数名词 应采用how many
例如,多少钱（钱是不可数名词） how much money do you need?你需要多少钱 应采用how much